The nightmare moon is the first blue moon of the year. It is a time when you see your deepest darkest fear. To find it. Watch the nightmare moon from 11:50 to 12:10 and after that time your fear will be within your mind. It was proven to work for me atleast. Comment your thoughts of it.

Dating back to the 1800's the term "blue moon" was used by the Farmer's Almanac to denote the appearance of a third full Moon in a season where four full Moon's will occur. Since there are normally 12 full Moon's a year (one per month), this works out to three per quarter (three month period). However, occasionally a quarter will see four full Moon's.

The naming arises because each Moon in a given season has its own name. This tradition of naming full Moons has existed for hundreds of years across many cultures. The names generally accepted today are those coming from the Farmer's Almanac.

For instance, during the second quarter of the year, the Moons are named Pink (April), Flower (May) and Strawberry (June). However, should another full Moon appear during this quarter it would be called, by default, a Blue Moon. Since the third of the four full Moon's in a quarter is called the Blue Moon, the order of Moon's in the second quarter of the year would be Pink, Flower, Blue and Strawberry.

Since Blue Moons only occur about once every three years, it became becomes a convenient measure of a long period of time, therefore giving rise to the cliche "once in a blue moon".

There are several different ways of naming the Full Moons, based on which path or faith you fall into. True, Blue Moons are the second occurring Full Moon in any given month. And it does take a span of years for this to occur again, with a few exceptions. There was recently a year where there were two Blue Moons. Can you find out which one? It occurred on August 2nd and September 1st 2012, two consecutive months which contained Blue Moons. Quite Existential! I am not going to do a ginormous listing (oh my god that word is in the dictionary!? lol) of all the different ways of describing each Full Moon. So, I have listed here a website that I like, where the research has been done and spelled out at length. http://www.paganspath.com/magik/moonnames.htm Other than that, there is always wikipedia...
Love and Light
Patience is a virtue.
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